1. Field of the Invention
The present invention relates to tools utilizing a mechanical power takeoff. More specifically, the present invention relates to a mechanized tool that generates a reciprocating motion with power strokes in both directions: such a tool being especially useful for applications such as hoes, thatching forks, and the like. More generally, the present invention relates to any application where constant, powerful, reciprocating motion is desired as an end product: agitation of an inclined bed of slurry in a mining operation, for example. The field of agriculture is seen as the most likely benefactor from the novel aspects of this invention. However, the fields of mechanical construction, manufacturing, and surgery could also benefit.
Thus it can be seen that the potential fields of use for this invention are myriad, and the particular preferred embodiment described herein is in no way meant to be limiting the particular field chosen for exposition of the details of the invention.
2. Description of the Prior Art
In preparing the ground for cultivation, it is necessary to loosen the soil. Additionally, while the plants are growing, weeding requires the disturbing of the soil between the cultivated rows. Since time immemorial, tools such as hoes have been used for this purpose. The motion used to properly utilize these types of tools is a reciprocating one: back and forth, or rectilinear. As the user bends over and moves the tool head back and forth, both back pain and upper body fatigue can result. The present invention seeks to address this problem by providing a mechanism that takes a rotating power takeoff and converts the same into rectilinear reciprocating motion of a single shaft (or multiple shafts--the present invention could be easily adapted to have more than one shaft, as will be seen below) that is attached to the tool head. The construction of the present invention allows for power strokes in both directions. This motion would be useful with tool heads such as blade hoes, thatch rakes, and the like. During a search at the U.S. Patent and Trademark Office, the following patents were uncovered that relate to the instant invention:
First is U.S. Pat. No. 3,406,761 issued on Oct. 22, 1968 to Thomas H. Ryan discloses a power tool wherein a pivotable power cylinder carries a rod therein that includes a universal tool attachment. The cylinder is attached to a frame with an upstanding carriage that includes the motor and the reservoir for activation of the cylinder. Contrast this to the present invention where the constantly reciprocating motion of the tool head is induced in such a way that the power is delivered in both directions of the stroke.
In U.S. Pat. No. 4,353,422 issued on Oct. 12, 1982 to James H. Bennett, Jr. there is disclosed a hand held machine with an oscillating tool. A gearmotor and a drive shaft connected to various linkages provide an oscillating, up and down, back and forth motion, similar to that of the standard hoeing, or raking motion. This is dissimilar from the present invention in that the reciprocating motion produced by the instant invention substantially lies in a single plane, thus keeping the tool head attached thereto in constant contact with the work area.
U.S. Pat. No. 4,122,902 issued on Oct. 31, 1978 to Warren A. Alexander discloses a motorized gardening tool wherein a first reciprocating motion is converted to a second motion at a substantial angle to the first. This second motion drives a tool head that is carried on a series of leaf spring connected linkage members. Contrast this to the present invention wherein the rotating power takeoff is connected to a flywheel that includes a cam follower to induce the reciprocating motion of the tool head carrier.
In U.S. Pat. No. 4,553,606 issued on Nov. 19, 1985 to William T. Arnold discloses a sod cutting machine that has a pair of mirror image under and side cutting knives. Eccentric stub shafts 180.degree. out of phase attached to the linkage arms drive the blades in oppositely reciprocating motions. This is clearly unlike the present invention, in that no single reciprocating tool carrying portion is discussed.
U.S. Pat. No. 4,305,470 issued on Dec. 15, 1981 to Elbert J. Anderson there is disclosed a power hoe with a reciprocating cutting head. A rotating drive shaft terminates in a drive plate carrying a drive pin. This pin is inserted into a piston carried by a sleeve. This is attached to the cutting head of a tool to provide reciprocating motion thereto. This is dissimilar from the present invention in that the cutting head is reciprocated through a swivelling linkage instead of a straight rectilinear motion in the tool carrying shaft provided in the instant invention.
Lastly, U.S. Pat. No. 4,541,492 issued on Sep. 17, 1985 to John Motruck discloses an earth working tool head. A rotating drive shaft is connected by a pair of cooperating bevel gears to an axle that carries, at either of its ends, a pair of fixed disk elements. These have pins located 180.degree. out of phase with one another and, thus, transmit pendulum-like movement to a pair of linked earth cutting blades. This is seen to be unlike the present invention, as no rectilinear reciprocating motion in a tool carrying portion is disclosed.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.